Well I'll be darned, here's another hint at circa 2200 BC.
Blam, have you ever seen any pics of the British "hill-forts", particularly the big ones that involved moving one hell of a lot of dirt? Some years back I hypothesized that they might be some kind of refuges for local populations against encroachment from the sea. I also believe that one of the reasons for ancient interest in the heavens was that they KNEW from experience that violent death from above was always a threat.
Yup. Many anthropologists think all the talk about dragons, serpents, snakes and swords in the heavens are descriptions of comets/meteorites. You really ought to read Mike Baillie's book, Exodus To Arthur.
Did you know that King Arthur's father was named Pendragon?
I have a different take on the reason for the ancient's interest in the skies. Nights for the primatives were boring; mind-numbingly, starkly, excruciatiatingly boring. If you have ever spent a few weeks in a primative setting without lights, radios or other diversions you know what I mean.
There were always the skies: Sparkling, moving, mysterious. It's no wonder that all ancient cultures focused so much on the night skies.